Rasa Dalibagaitė1, Aistė Buitvidaitė1, Gitana Ramonienė2
1Lithuanian University of Health Sciences, Medical Academy, Faculty of Medicine, Kaunas, Lithuania
2Department of Obstetrics and Gynecology, Faculty of Medicine, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
Abstract
Background. The level of obesity among women of childbearing age continues to increase. Obesity in women is a common problem, and its effects on pregnancy are usually overlooked. The study aimed to assess the common method of delivery and the rates of induction and augmentation of labor among obese pregnant women.
Aim: to assess the common method of delivery and the rates of induction and augmentation of labor among obese pregnant women.
Materials and methods. A retrospective case-control study was conducted in the Lithuanian University of Health and Sciences (LUHS) hospital, using data from their birth registry. Two groups of pregnant women, who gave birth in 2021 were analyzed and compared. The first group consisted of 334 obese pregnant women, and the second group consisted of 324 pregnant women with normal BMI. IBM SPSS software was used for data processing. Results with values of p < 0.05 were considered statistically significant.
Results. Results provide that more cesarean section surgeries (33.3 % vs 18.2 %) and vacuum extractions (1.5 % vs 1.2 %) were performed on obese pregnant women compared to women with normal BMI. Natural delivery was more common among women with normal BMI (p < 0.001). Obese pregnant women were more likely to experience induction or augmentation of labor. In comparison to women with normal BMI, induction, and augmentation of labor were more often performed on obese pregnant women (36.4 % vs 42.5 % and 12.4 % vs 25.8 % respectively). Women with normal BMI tended to have fewer interventions for initiation of labor as compared to obese pregnant women (51.2 % vs 31.7 % respectively).
Conclusion. In our study, cesarean section surgery, induction, and augmentation of labor were more frequent amongobese pregnant women than among normal-weight pregnant women.
Keywords: obesity, obstetric outcomes, cesarean section surgery, labor induction, augmentation.
https://doi.org/10.53453/ms.2023.5.16
Obesity and labor induction, augmentation and cesarean section
Rasa Dalibagaitė
1
, Aistė Buitvidaitė
1
, Gitana Ramonienė
2
1
Lithuanian University of Health Sciences, Medical Academy, Faculty of Medicine, Kaunas, Lithuania
2
Department of Obstetrics and Gynecology, Faculty of Medicine, Medical Academy, Lithuanian University of
Health Sciences, Kaunas, Lithuania
Abstract
Background. The level of obesity among women of childbearing age continues to increase. Obesity in women is
a common problem, and its effects on pregnancy are usually overlooked. The study aimed to assess the common
method of delivery and the rates of induction and augmentation of labor among obese pregnant women.
Aim: to assess the common method of delivery and the rates of induction and augmentation of labor among obese
pregnant women.
Materials and methods. A retrospective case-control study was conducted in the Lithuanian University of Health
and Sciences (LUHS) hospital, using data from their birth registry. Two groups of pregnant women, who gave
birth in 2021 were analyzed and compared. The first group consisted of 334 obese pregnant women, and the
second group consisted of 324 pregnant women with normal BMI. IBM SPSS software was used for data
processing. Results with values of p < 0.05 were considered statistically significant.
Results. Results provide that more cesarean section surgeries (33.3 % vs 18.2 %) and vacuum extractions (1.5 %
vs 1.2 %) were performed on obese pregnant women compared to women with normal BMI. Natural delivery was
more common among women with normal BMI (p < 0.001). Obese pregnant women were more likely to
experience induction or augmentation of labor. In comparison to women with normal BMI, induction, and
augmentation of labor were more often performed on obese pregnant women (36.4 % vs 42.5 % and 12.4 % vs
25.8 % respectively). Women with normal BMI tended to have fewer interventions for initiation of labor as
compared to obese pregnant women (51.2 % vs 31.7 % respectively).
Conclusion. In our study, cesarean section surgery, induction, and augmentation of labor were more frequent
amongobese pregnant women than among normal-weight pregnant women.
Keywords: obesity, obstetric outcomes, cesarean section surgery, labor induction, augmentation.
Journal of Medical Sciences. 11 May, 2023 - Volume 11 | Issue 4. Electronic - ISSN: 2345-0592
Medical Sciences 2023 Vol. 11 (4), p. 147-152, https://doi.org/10.53453/ms.2023.5.16
147
1. Introduction
The prevalence of obesity continues to increase
worldwide. According to the World Health
Organization (WHO) in 2016 39 % of adults 18
years old and older were overweight and 13 % were
obese (1). Body mass index is used to classify
overweight and obese in adults, where BMI
< 18.5 kg/m
2
- underweight, BMI 18.5 – 24.9 kg/m
2
- normal weight range, BMI 25 – 29.9 kg/m
2
-
overweight, BMI ≥ 30 kg/m
2
is considered obesity
(2). Compared to males, women are more likely to
become overweight or obese than males (3). Obesity
is a crucial issue in every woman’s life as it might
affect a woman’s reproductive health and pregnancy
(4). Obese women have an increased risk of
infertility, gestational diabetes, preeclampsia,
cesarean section surgery, fetal macrosomia, and
neonatal morbidity (5,6). The complex etiology of
obesity circumscribing genetic, psychological, and
socioeconomic factors makes it difficult to develop
successful interventions for weight management (3).
The study aimed to evaluate the incidence of
cesarean section surgeries, labour induction, and
labour augmentation among obese pregnant
Lithuanian women.
2. Materials and methods
2.1. Data collection
A retrospective case – control study was conducted
in the Lithuanian University Health and Sciences
Hospital (LUHS), Clinic of Obstetrics and
Gynecology, using data from their birth registry.
Two groups of patients were included. The first
group – obese pregnant women with BMI
≥ 30 kg/m
2
. The second group – pregnant women
with a BMI of 18.5 – 24.9 kg/m
2
. The study did not
include multiparous and overweight (BMI 25 –
29.9 kg/m2) pregnant women. After collecting the
data, two groups of pregnant women who gave birth
in 2021 were analyzed and compared. The first
group consisted of 334 obese pregnant women, and
the second group consisted of 324 pregnant women
with normal BMI (body mass index).
2.2. Data analysis
IBM SPSS software was used for data processing.
Pearson‘s correlation was used to compare
quantitative variables to find a linear relationship.
Results with values of p < 0.05 were considered
statistically significant.
2.3. Ethics
Approval to conduct this study has been granted by
the Lithuanian University of Health Sciences Center
for Bioethics (reference number: BEC – MF – 443).
3. Results
3.1. The method of delivery among obese
pregnant women
As shown in the graph, most women gave birth by
natural delivery in 2021. Results provide that more
cesarean section surgeries and vacuum extractions
were performed on obese pregnant women
compared to women with normal BMI (33.3 % vs
18.2 % and 1.5 % vs 1.2 % respectively) (p < 0.001).
Natural delivery was more common among women
with normal BMI (p < 0.001) (Figure 1). In this
study, the most common indications for cesarean
section surgery for obese women were: suspected
unstable condition of the fetus, gestational diabetes,
and non – progressive labor. For women with
normal BMI, the most common indications for
cesarean section surgery were: gestational diabetes,
suspected unstable condition of the fetus, failed
labor induction, and breech presentation.
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Figure 1. Method of delivery based on a woman's weight.
3.2. Induction and augmentation of labor among
obese pregnant women
As shown in the second graph, obese pregnant
women were more likely to experience induction or
augmentation of labor. Compared to women with
normal BMI, induction, and augmentation of labor
were more often performed on obese pregnant
women (36.4 % vs 42.5 % and 12.4 % vs 25.8 %
respectively) (p < 0.001). Women with normal BMI
tended to have fewer interventions for initiating
labor than obese pregnant women (51.2 % vs 31.7 %
respectively) (Figure 2).
Figure 2. The number of women to whom the labor initiation method was adapted.
4. Discusion
The results of our study indicate that obese pregnant
women experience labor augmentation twice asoften
astheir lean counterparts. In addition, statistically
significantly more obese patients experience labor
induction (p < 0.001). Results of a cohort study,
conducted in Spain, show that induction of labor was
performed more often on obese pregnant women
than normal BMI patients, 59.6 % and 47.3 %
respectively (7). These results occur due to
physiological changes in obese women during labor
- slower progression of labor which is a risk factor
of labor dystocia, chorioamnionitis, emergency
cesarean section (8). Moreover, there is a higher rate
of post-term pregnancies, cases of diabetes, chronic
and gestational hypertension, preeclampsia (7).
Therefore the need for labor induction and
augmentation is increasing among obese pregnant
patients. Carlhäll and co-authors conducted research
comparing median labor time among obese women
and normal BMI pregnant patients. The results of the
study show significantly longer labor duration in the
80.6
18.2
1.2
65.3
33.3
1.5
0 10 20 30 40 50 60 70 80 90
Natural delivery
Cesarean section surgery
Vacuum Extraction
Percentage of women
Method of delivery
Obese pregnant women Women with normal BMI
86
142
106
40
118
166
0
50
100
150
200
Augmentation of labor Induction of labor No method was used
Number of women
Method for initiation of labor
Obese pregnant women Women with normal BMI
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obese pregnant women group, class I obesity - 9.1 h;
class II obesity 9.2 h and class III obesity - 9.8 h,
while normal BMI women’s median labor time was
8.8 h (9). It is thaught that the latent phase of labor
is longer and there are more post-term deliveries
among obese women because of impaired
contractility of myometrium. The main
physiological factors contributing to weaker
contractility of the uterus are higher levels of leptin
and cholesterol in the system which impaires the
calcium flow in the myometrium weakening the
muscle contractility (10,11). In fact, because of the
weight, obese women require higher oxytocin doses
to have an effect during labor interventions
(cumulative oxytocin dose among normal weight
women was 2278 mU and among obese patients
4082 mU (p<0.0001)) and, results indicate, longer
birth after the oxytocin infusion (8). In addition to
that, obese pregnant women have a higher risk of
cesarean section surgery after labor induction than
women with normal BMI. In a retrospective cohort
study published in 2019 by Carlhall S and other co-
authors, the CS rate among underweight women was
7.4 %, and among women with BMI ≥ 40 kg/m2 –
22.0 % (12). In a retrospective cohort study, the rate
of vaginal delivery after induction of labor among
women with normal BMI was 83.0 %, and among
women with class III obesity – 61.8 % (13).
In our study, the rate of cesarean section surgeries
was almost two times higher among obese pregnant
women compared to normal-weight pregnant
women (p < 0.001). According to the Centers for
Disease Control and Prevention, in the United
States, in 2020 the cesarean section (CS) rate was
31.8 %. CS rates were lowest among underweight
and normal-weight women (20.7 % vs 25.1 %
respectively). As BMI increased, the rate of CS rose
steadily and was as high as 52.3 % among women
with morbid obesity (BMI of 40 and higher) (14). In
a cross-sectional study, the risk of CS was 4.46 times
higher in class I obesity compared to normal-weight
pregnant women and 3.04 times higher than the risk
in the overweight group (15). Usually, obesity is not
an indication for cesarean section surgery, although
CS rates might increase due to complications that
arise from obesity. For obese pregnant women,
cervical ripening is often slower than for normal-
weight pregnant women. The slower cervical
ripening can often be interpreted as primary dystocia
and might lead to unnecessary interventions and
contribute to increased CS rates (16). In the study
published in 2022 by Bjorklund J. and other authors,
it is proven that for women with higher BMI, the
latency phase extends to a cervical dilatation of five
centimeters. This is crucial in clinical practice to
avoid the risk of CS to women that have not yet left
the latency phase (17). Women with higher BMI
have a significantly increased risk of fetal weight
over 4000 g (fetal macrosomia) which might lead to
an increased risk of cesarean section surgery. Based
on a cohort study there is a 60 % risk of delivering a
macrosomic neonates for overweight and 90% risk
for obese pregnant women (18). In a meta-analysis
published in 2017 by Dai RX and other authors, prie-
pregnancy maternal obesity was associated with
fetal macrosomia (OR 1.93) (19).
Maternal obesity is associated with other
complications, such as increased rates of midline
vertical incision, CS wound complications, and
longer operative time. In a study published by
Conner SN, Verticchio JC, and others, BMI was
associated with an increased risk of wound
complications. The higher the BMI, the greater the
risk of developing wound complications: BMI 30.0
– 39.9, 9.2 %; BMI 40.0 – 49.9, 16.8 %; BMI ≥ 50,
22.9 % (20). In a cross-sectional study published by
Khalifa E and co-authors in 2021, the intraoperative
duration of CS was longer as compared to
overweight and normal-weight pregnant women
(65.6 ± 14; 54.0 ± 12.5 and 50.9 ± 17.9 minutes
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respectively) (21). Developing a multidisciplinary
approach for overweight or obese women before or
during pregnancy might help reduce the rates of
negative obstetric and neonatal outcomes.
5. Conclusions
In our study, cesarean section surgery, induction,
and augmentation of labor were more frequent
among obese pregnant women than on normal-
weight pregnant women.
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